gcc/ada/s-fileio.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                       S Y S T E M . F I L E _ I O                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides support for the routines described in (RM A.8.2)
  35 --  which are common to Text_IO, Direct_IO, Sequential_IO and Stream_IO.
  36
  37 with Interfaces.C_Streams;
  38
  39 with System.File_Control_Block;
  40
  41 package System.File_IO is
  42
  43    package FCB renames System.File_Control_Block;
  44    package ICS renames Interfaces.C_Streams;
  45
  46    ---------------------
  47    -- File Management --
  48    ---------------------
  49
  50    procedure Open
  51      (File_Ptr  : in out FCB.AFCB_Ptr;
  52       Dummy_FCB : FCB.AFCB'Class;
  53       Mode      : FCB.File_Mode;
  54       Name      : String;
  55       Form      : String;
  56       Amethod   : Character;
  57       Creat     : Boolean;
  58       Text      : Boolean;
  59       C_Stream  : ICS.FILEs := ICS.NULL_Stream);
  60    --  This routine is used for both Open and Create calls:
  61    --
  62    --    File_Ptr is the file type, which must be null on entry
  63    --    (i.e. the file must be closed before the call).
  64    --
  65    --    Dummy_FCB is a default initialized file control block of appropriate
  66    --    type. Note that the tag of this record indicates the type and length
  67    --    of the control block. This control block is used only for the purpose
  68    --    of providing the controlling argument for calling the write version
  69    --    of Allocate_AFCB. It has no other purpose, and its fields are never
  70    --    read or written.
  71    --
  72    --    Mode is the required mode
  73    --
  74    --    Name is the file name, with a null string indicating that a temporary
  75    --    file is to be created (only permitted in create mode, not open mode)
  76    --
  77    --    Creat is True for a create call, and false for an open call
  78    --
  79    --    Text is set True to open the file in text mode (w+t or r+t) instead
  80    --    of the usual binary mode open (w+b or r+b).
  81    --
  82    --    Form is the form string given in the open or create call, this is
  83    --    stored in the AFCB, but otherwise is not used by this or any other
  84    --    routine in this unit (except Form which retrieves the original value)
  85    --
  86    --    Amethod indicates the access method
  87    --
  88    --      D = Direct_IO
  89    --      Q = Sequential_IO
  90    --      S = Stream_IO
  91    --      T = Text_IO
  92    --      W = Wide_Text_IO
  93    --
  94    --    C_Stream is left at its default value for the normal case of an
  95    --    Open or Create call as defined in the RM. The only time this is
  96    --    non-null is for the Open call from Ada.xxx_IO.C_Streams.Open.
  97    --
  98    --  On return, if the open/create succeeds, then the fields of File are
  99    --  filled in, and this value is copied to the heap. File_Ptr points to
 100    --  this allocated file control block. If the open/create fails, then the
 101    --  fields of File are undefined, and File_Ptr is unchanged.
 102
 103    procedure Close (File_Ptr : access FCB.AFCB_Ptr);
 104    --  The file is closed, all storage associated with it is released, and
 105    --  File is set to null. Note that this routine calls AFCB_Close to perform
 106    --  any specialized close actions, then closes the file at the system level,
 107    --  then frees the mode and form strings, and finally calls AFCB_Free to
 108    --  free the file control block itself, setting File.all to null. Note that
 109    --  for this assignment to be done in all cases, including those where
 110    --  an exception is raised, we can't use an IN OUT parameter (which would
 111    --  not be copied back in case of abnormal return).
 112
 113    procedure Delete (File_Ptr : access FCB.AFCB_Ptr);
 114    --  The indicated file is unlinked
 115
 116    procedure Reset (File_Ptr : access FCB.AFCB_Ptr; Mode : FCB.File_Mode);
 117    --  The file is reset, and the mode changed as indicated
 118
 119    procedure Reset (File_Ptr : access FCB.AFCB_Ptr);
 120    --  The files is reset, and the mode is unchanged
 121
 122    function Mode (File : FCB.AFCB_Ptr) return FCB.File_Mode;
 123    --  Returns the mode as supplied by create, open or reset
 124
 125    function Name (File : FCB.AFCB_Ptr) return String;
 126    --  Returns the file name as supplied by Open or Create. Raises Use_Error
 127    --  if used with temporary files or standard files.
 128
 129    function Form (File : FCB.AFCB_Ptr) return String;
 130    --  Returns the form as supplied by create, open or reset
 131    --  The string is normalized to all lower case letters.
 132
 133    function Is_Open (File : FCB.AFCB_Ptr) return Boolean;
 134    --  Determines if file is open or not
 135
 136    ----------------------
 137    -- Utility Routines --
 138    ----------------------
 139
 140    --  Some internal routines not defined in A.8.2. These are routines which
 141    --  provide required common functionality shared by separate packages.
 142
 143    procedure Chain_File (File : FCB.AFCB_Ptr);
 144    --  Used to chain the given file into the list of open files. Normally this
 145    --  is done implicitly by Open. Chain_File is used for the special cases of
 146    --  the system files defined by Text_IO (stdin, stdout, stderr) which are
 147    --  not opened in the normal manner. Note that the caller is responsible
 148    --  for task lock out to protect the global data structures if this is
 149    --  necessary (it is needed for the calls from within this unit itself,
 150    --  but not required for the calls from Text_IO and Wide_Text_IO that
 151    --  are made during elaboration of the environment task).
 152
 153    procedure Check_File_Open (File : FCB.AFCB_Ptr);
 154    --  If the current file is not open, then Status_Error is raised.
 155    --  Otherwise control returns normally (with File pointing to the
 156    --  control block for the open file.
 157
 158    procedure Check_Read_Status (File : FCB.AFCB_Ptr);
 159    --  If the current file is not open, then Status_Error is raised. If
 160    --  the file is open, then the mode is checked to ensure that reading
 161    --  is permitted, and if not Mode_Error is raised, otherwise control
 162    --  returns normally.
 163
 164    procedure Check_Write_Status (File : FCB.AFCB_Ptr);
 165    --  If the current file is not open, then Status_Error is raised. If
 166    --  the file is open, then the mode is checked to ensure that writing
 167    --  is permitted, and if not Mode_Error is raised, otherwise control
 168    --  returns normally.
 169
 170    function End_Of_File (File : FCB.AFCB_Ptr) return Boolean;
 171    --  File must be opened in read mode. True is returned if the stream is
 172    --  currently positioned at the end of file, otherwise False is returned.
 173    --  The position of the stream is not affected.
 174
 175    procedure Flush (File : FCB.AFCB_Ptr);
 176    --  Flushes the stream associated with the given file. The file must be
 177    --  open and in write mode (if not, an appropriate exception is raised)
 178
 179    function Form_Boolean
 180      (Form    : String;
 181       Keyword : String;
 182       Default : Boolean)
 183       return    Boolean;
 184    --  Searches form string for an entry of the form Keyword=xx where xx is
 185    --  either Yes/No or y/n. Returns True if Yes or Y is found, False if No
 186    --  or N is found. If the keyword parameter is not found, returns the
 187    --  value given as Default. May raise Use_Error if a form string syntax
 188    --  error is detected. Keyword and Form must be in lower case.
 189
 190    function Form_Integer
 191      (Form    : String;
 192       Keyword : String;
 193       Default : Integer)
 194       return    Integer;
 195    --  Searches form string for an entry of the form Keyword=xx where xx is
 196    --  an unsigned decimal integer in the range 0 to 999_999. Returns this
 197    --  integer value if it is found. If the keyword parameter is not found,
 198    --  returns the value given as Default. Raise Use_Error if a form string
 199    --  syntax error is detected. Keyword and Form must be in lower case.
 200
 201    procedure Form_Parameter
 202      (Form    : String;
 203       Keyword : String;
 204       Start   : out Natural;
 205       Stop    : out Natural);
 206    --  Searches form string for an entry of the form Keyword=xx and if found
 207    --  Sets Start and Stop to the first and last characters of xx. Keyword
 208    --  and Form must be in lower case. If no entry matches, then Start and
 209    --  Stop are set to zero on return. Use_Error is raised if a malformed
 210    --  string is detected, but there is no guarantee of full syntax checking.
 211
 212    procedure Read_Buf
 213      (File : FCB.AFCB_Ptr;
 214       Buf  : Address;
 215       Siz  : Interfaces.C_Streams.size_t);
 216    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 217    --  that the file is open in read mode. Raises an exception if Siz bytes
 218    --  cannot be read (End_Error if no data was read, Data_Error if a partial
 219    --  buffer was read, Device_Error if an error occurs).
 220
 221    procedure Read_Buf
 222      (File  : FCB.AFCB_Ptr;
 223       Buf   : Address;
 224       Siz   : Interfaces.C_Streams.size_t;
 225       Count : out Interfaces.C_Streams.size_t);
 226    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 227    --  that the file is open in read mode. Device Error is raised if an error
 228    --  occurs. Count is the actual number of bytes read, which may be less
 229    --  than Siz if the end of file is encountered.
 230
 231    procedure Append_Set (File : FCB.AFCB_Ptr);
 232    --  If the mode of the file is Append_File, then the file is positioned
 233    --  at the end of file using fseek, otherwise this call has no effect.
 234
 235    procedure Write_Buf
 236      (File : FCB.AFCB_Ptr;
 237       Buf  : Address;
 238       Siz  : Interfaces.C_Streams.size_t);
 239    --  Writes size_t bytes to File.Stream from Buf. The caller has checked
 240    --  that the file is open in write mode. Raises Device_Error if the
 241    --  complete buffer cannot be written.
 242
 243    procedure Make_Unbuffered (File : FCB.AFCB_Ptr);
 244
 245    procedure Make_Line_Buffered
 246      (File     : FCB.AFCB_Ptr;
 247       Line_Siz : Interfaces.C_Streams.size_t);
 248
 249    procedure Make_Buffered
 250      (File     : FCB.AFCB_Ptr;
 251       Buf_Siz  : Interfaces.C_Streams.size_t);
 252
 253 private
 254    pragma Inline (Check_Read_Status);
 255    pragma Inline (Check_Write_Status);
 256    pragma Inline (Mode);
 257
 258 end System.File_IO;